There is limited evidence comparing non-operative treatment to ACL reconstruction in patients with recurrent instability, but it supports that the practitioner might perform ACL reconstruction because this procedure reduces pathologic laxity.

Rationale
One prospective comparative study was included.24 With respect to recurrent instability, this study compared two groups of interest – an ACL-unstable group that ultimately did not undergo ACL reconstruction despite persistent pathologic laxity (Group II in the article, considered "copers") as well as an ACL-unstable group that ultimately did undergo late ACL reconstruction following recurrent instability (Group IV in the article).  The late ACL reconstructions in Group IV occurred 9 to 84 months after injury.  Of the 147 patients in Group II, only 11 had meniscal surgery. Of the 46 patients in Group IV, 29 had meniscal surgery. The article also reports an ACL-stable group with hemarthrosis (Group I) and an ACL-unstable group that underwent early ACL reconstruction (Group III).

At final evaluation of symptoms, 18% of the non-ACL-reconstructed, unstable patients (Group II) reported giving way with sports while only 3% of the late-ACL-reconstructed patients (Group IV) reported giving way with sports.  Similarly, 9% of the non-ACL-reconstructed, unstable patients (Group II) reported giving way with activities of daily life, while only 3% of the late-ACL-reconstructed patients (Group IV) reported giving way with activities of daily life. Objective instrumented and physical examination findings paralleled these subjective findings. This is without undergoing ACL reconstruction (Group II), 84% of patients demonstrated positive KT-1000 arthrometer measurements (>3 mm side-to-side difference with manual maximum testing) and 84% had positive pivot shift testing.  Following late ACL reconstruction (Group IV), 70% of patients demonstrated positive KT-1000 arthrometer measurements and 52% had positive pivot shift testing.

Possible Harms of Implementation
As with all surgery procedures, there are surgical risks and complications including but not limited to graft failure, arthrofibrosis, infection, neurovascular injury, and anesthetic complications.

Future Research
Further research is needed to assess the outcomes in patients with recurrent instability.  Specifically, we need to follow these patients after non-operative treatment as well as after ACL reconstruction.
 
  1. (24) Daniel DM, Stone ML, Dobson BE, Fithian DC, Rossman DJ, Kaufman KR. Fate of the ACL-injured patient. A prospective outcome study. Am J Sports Med 1994;22:632-644.